Minimum and maximum sample values are commonly required in computer graphics operations such as anti-aliasing processes to reduce or eliminate aliasing effects. Aliasing refers to an effect resulting from image sampling and reconstruction that results in distortions and artifacts in the image. More specifically, spatial aliasing results in artifacts because of limited spatial resolution in generating a computer image.
To avoid or reduce the incidence of aliasing, anti-aliasing algorithms may be implemented. For example, multisample anti-aliasing (MSAA), in which multiple samples for each pixel are obtained and processed, may be utilized to reduce aliasing effects.
However, MSAA operation conventionally requires the saving of the multiple samples and the computation of the minimum or maximum sample in the shader. Because the samples are typically stored in separate planes (a memory array being partitioned into multiple memory planes), the memory overhead required for the determination of minimum and maximum sample values can be very significant.